Individuals in emergency conditions must deal with a number of adverse conditions when attempting to leave, or assist others in leaving, the affected area. A critical factor in navigating locations in emergency conditions can be a reduced visibility caused by obscurants such as smoke or other airborne particulate matter. In very low visibility conditions, individuals unfamiliar with the environment are reluctant to evacuate through an obscurant sufficiently dense to reduce visibility below ten meters. Individuals familiar with exit routes are able to evacuate through more dense obscurants, at around five meters of visibility. At lower visibility levels, however, the behavior of individuals changes, and more reliance is placed on their feeling their way forward, while crawling along walls, as opposed to relying on visual information. It will be appreciated that this can significantly slow progression through the obscured environment and may result in prolonged exposure to toxic gases.